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I am happy to report that the SCE guys fixed up everything. I am now happily charging at 40A at a stable 232V.
Unfortunately and fortunately, I had left town for the weekend... I'm happy that I didn't have to deal with my dogs and the ~5 hour electricity outage; but I'm sad to have missed watching the work and missing the details of the changes.
I can see they did a lot of work. I see lots of new wires for my neighbors' runs. I have new fat gauge 0 to my house. I see 2 new transformer cans on the two nearest poles. It looks like a nice general overhaul of all the infrastructure behind my house.
Unfortunately and fortunately, I had left town for the weekend... I'm happy that I didn't have to deal with my dogs and the ~5 hour electricity outage; but I'm sad to have missed watching the work and missing the details of the changes.
I can see they did a lot of work. I see lots of new wires for my neighbors' runs. I have new fat gauge 0 to my house. I see 2 new transformer cans on the two nearest poles. It looks like a nice general overhaul of all the infrastructure behind my house.
hughconn
Member
Hi, I've been having the same, or very similar, issue. I've had my electrician replace breakers and outlet. No luck solving the problem, now it's time to get the utility involved. I was thrilled to see your postings and resolution. My question is this, "What do you tell the utility customer service rep when you call?" My fear is that I waste an hour on the phone being bounced around from dept. to dept. because the folks at the utility don't know what an electric car is (exaggeration for effect). But you get my point. Any help is appreciated.
@hughconn Do Not mention anything about your electric car when you call in. Just tell them "I am having Voltage Drop problem throughout the house and I have already hired an electrician who tested everything inside the house."
Have you duplicated the Voltage Drop by turning of any/all electric appliances to simulate the same current draw as the Tesla? If not, before calling the utility, I would turn on the stove, dryer, and AC(s) all at once and see if you get the same drop. If so, it will either be the electric utility equipment or your meter base.
Have you duplicated the Voltage Drop by turning of any/all electric appliances to simulate the same current draw as the Tesla? If not, before calling the utility, I would turn on the stove, dryer, and AC(s) all at once and see if you get the same drop. If so, it will either be the electric utility equipment or your meter base.
hughconn
Member
Thanks guys, great feedback. What test should I be having done? Is there a form of stress testing that an electrician can do on the circuit?
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So that's the limit of my useful knowledge. I'm a pretty damn good home electrician. I've rewired most of my house. I did all of the wiring in my kitchen. I've added multiple circuits all over the house. I can do wire and conduit size calculations. I designed and installed my own rooftop PV. Just yesterday I diagnosed and fixed a hot ground problem at my friend's house. I feel pretty confident in my skills for everything on the load side of my main breaker.
What I can't do is look up at supply conductors 15' in the air and tell you the gauge
Did you read the first page of this post? There are several suggestions for testing and diagnosis. Do you know if you are having voltage drop?
whitecotton
Member
This is a little different question, but what os the purpose/ difference between 240v and 208v "commercial" power.
@whitecotton Very good question. However, the answer is not a simple one. But, I will try to put it into layman's terms so as to not break out the mathematical formulas. And, for those that are electrical engineers, please don't argue with what I am about to say, as I am one too, but want to simplify a complex answer.
So, in the US, the electric utilities standardized on Alternating Current for the electrical power grid. The power grid consists of Generation Plants, Transmission Lines, DIstribution Substations, Distribution Lines and Service Drops.
Voltage is the Potential Difference as measured between two electrical conductors, called phases (P). Additionally, there is another conductor in AC Power, and that is the Neutral conductor (N). Voltage measurements can be taken either P - P or P - N. In AC power theory, AC voltage is written NNN VAC to indicate Voltage AC. I am going to use V instead of VAC just to make it easy to read, but know that it is proper to identify it as VAC when speaking about AC voltage. Direct Current voltage would be labeled VDC. We are speaking here of AC voltage only.
Common US Voltages - There are many numbers you hear people throw around for voltage - 120, 110, 115, 208, 220, 240, 277, 480 etc. This has to do with human nature, time and the full lack of understanding of electrical theory - Just as you called 208 'commercial' power which isn't necessarily true at all. In all actuality, the reason for so many numbers is that there are several types of wiring configurations that result in different voltage readings that I will explain below. But, to give you the proper names of service voltages, there is 120V Single Phase, 120/240 Single Phase, 120/208 Single Phase, 120/208V Three Phase WYE, 277/480V Three Phase WYE, 120/240/208V Network, 240V DELTA and 480V DELTA. There are several other specialty configuration, but that is for another day.
Service Drops are the electrical connection from a Power Transformer to the Customer's premises. Depending on the types of load that will be connect, there are different configurations of power transformer wiring.
Single Phase, WYE and Delta - The three main types of wiring are Single Phase, Three-Phase WYE and Three- Phase Delta. Delta configurations supply a greater amount of current per phase and are mainly used for industrial motor load and also for radio towers. The most common connections are the remaining two, Single Phase and Three-Phase WYE.
Single Phase
The name Single Phase actually comes from the connection of the power transformer to a single phase of distribution lines that run down the road. The power transformer is connected with one tap to the 'Hot' wire and the second to the Neutral Wire. The power transformer 'steps down' the distribution voltage to a safer level that can be used in a home or business. On a single phase power transformer, there are three output connections: Line 1 (L1), Line 2 (L2) and Neutral. The voltage measured across L1 - L2 is 240V. The voltage measured across L1 - N is 120V and the voltage measured across L2 - N is 120V. So, for residential services and small businesses, a single phase service is all that is needed and it supplies 120V P-N and 240V P-P.
Three Phase WYE
The name Three Phase Power again actually comes from the connection to the distribution lines. In the case of Three Phase service, there will need to be four wires at the road, three 'Hot' wires and one 'Neutral'. I need to now jump back to where the power comes from. US Power generators generate three-phase power. The generator spins 360 degrees. There are three taps on the generator that are evenly spaced around the generator, thus they are located every 120 degrees. This is important to remember - 120 degree separation between phases. I will not discuss the generation voltage, transmission voltage or distribution voltage, as they vary widely and don't have much meaning for your question.
So, there are three 'hot' phases from the generator, to the transmission lines, to the distribution substations, to the distribution lines. But, now we need to get three phase power to the customer for use in a commercial or industrial setting, or maybe even a backyard welding or woodworking shop. So, to get three phase power to the customer, the utility 'hangs' three single phase transformers and connects one transformer to each of the 'hot' phases and all three to the neutral. For the service drop, they tie all of the secondary neutral lugs together and send one neutral wire to the customer. Then, Instead of sending both L1 and L2 of each of the three transformers, or six phases, they simply send all three of the L1s to the customer. So, the service drop now consists of four wires, three 'hot' and one neutral. For this discussion, we will name each of the hot wires L1, L2 and L3 and the neutral will be N.
As with the Single Phase voltage measurement, L1 - N, L2 - N and L3-N will all be 120V. However, the tricky part comes when voltage is measured P-P. Because L1, L2 and L3 are 120 degrees apart from each other, vector math comes into play. I won't try to prove the mathematical theorem, just know that with two vectors 120 degrees apart from each other, there actual distance is the Square Root of Three or ~1.73. Therefore, When measuring P - P 120V phases, the voltage will be 208V. So, L1 - L2 = 208V, L2 - L3 = 208V and L3 - L1 = 208V.
Clarification on 208V being 'Commercial' - It's not
Some utilities use a Three Phase Wye, 120/208V power transformer to feed a condominium complex. They do this because it is cheaper to set a single transformer for both single phase and three phase then to have multiple three-phase and single phase transformers. In this case, some condominiums and small businesses may actually have Single Phase 120/208V service drop and not 120/240V. Again, the reason is that the power company chose to feed the Single Phase service off of a Three-Phase 120/208V transformer.
I hope this helps and was not too technical.
So, in the US, the electric utilities standardized on Alternating Current for the electrical power grid. The power grid consists of Generation Plants, Transmission Lines, DIstribution Substations, Distribution Lines and Service Drops.
Voltage is the Potential Difference as measured between two electrical conductors, called phases (P). Additionally, there is another conductor in AC Power, and that is the Neutral conductor (N). Voltage measurements can be taken either P - P or P - N. In AC power theory, AC voltage is written NNN VAC to indicate Voltage AC. I am going to use V instead of VAC just to make it easy to read, but know that it is proper to identify it as VAC when speaking about AC voltage. Direct Current voltage would be labeled VDC. We are speaking here of AC voltage only.
Common US Voltages - There are many numbers you hear people throw around for voltage - 120, 110, 115, 208, 220, 240, 277, 480 etc. This has to do with human nature, time and the full lack of understanding of electrical theory - Just as you called 208 'commercial' power which isn't necessarily true at all. In all actuality, the reason for so many numbers is that there are several types of wiring configurations that result in different voltage readings that I will explain below. But, to give you the proper names of service voltages, there is 120V Single Phase, 120/240 Single Phase, 120/208 Single Phase, 120/208V Three Phase WYE, 277/480V Three Phase WYE, 120/240/208V Network, 240V DELTA and 480V DELTA. There are several other specialty configuration, but that is for another day.
Service Drops are the electrical connection from a Power Transformer to the Customer's premises. Depending on the types of load that will be connect, there are different configurations of power transformer wiring.
Single Phase, WYE and Delta - The three main types of wiring are Single Phase, Three-Phase WYE and Three- Phase Delta. Delta configurations supply a greater amount of current per phase and are mainly used for industrial motor load and also for radio towers. The most common connections are the remaining two, Single Phase and Three-Phase WYE.
Single Phase
The name Single Phase actually comes from the connection of the power transformer to a single phase of distribution lines that run down the road. The power transformer is connected with one tap to the 'Hot' wire and the second to the Neutral Wire. The power transformer 'steps down' the distribution voltage to a safer level that can be used in a home or business. On a single phase power transformer, there are three output connections: Line 1 (L1), Line 2 (L2) and Neutral. The voltage measured across L1 - L2 is 240V. The voltage measured across L1 - N is 120V and the voltage measured across L2 - N is 120V. So, for residential services and small businesses, a single phase service is all that is needed and it supplies 120V P-N and 240V P-P.
Three Phase WYE
The name Three Phase Power again actually comes from the connection to the distribution lines. In the case of Three Phase service, there will need to be four wires at the road, three 'Hot' wires and one 'Neutral'. I need to now jump back to where the power comes from. US Power generators generate three-phase power. The generator spins 360 degrees. There are three taps on the generator that are evenly spaced around the generator, thus they are located every 120 degrees. This is important to remember - 120 degree separation between phases. I will not discuss the generation voltage, transmission voltage or distribution voltage, as they vary widely and don't have much meaning for your question.
So, there are three 'hot' phases from the generator, to the transmission lines, to the distribution substations, to the distribution lines. But, now we need to get three phase power to the customer for use in a commercial or industrial setting, or maybe even a backyard welding or woodworking shop. So, to get three phase power to the customer, the utility 'hangs' three single phase transformers and connects one transformer to each of the 'hot' phases and all three to the neutral. For the service drop, they tie all of the secondary neutral lugs together and send one neutral wire to the customer. Then, Instead of sending both L1 and L2 of each of the three transformers, or six phases, they simply send all three of the L1s to the customer. So, the service drop now consists of four wires, three 'hot' and one neutral. For this discussion, we will name each of the hot wires L1, L2 and L3 and the neutral will be N.
As with the Single Phase voltage measurement, L1 - N, L2 - N and L3-N will all be 120V. However, the tricky part comes when voltage is measured P-P. Because L1, L2 and L3 are 120 degrees apart from each other, vector math comes into play. I won't try to prove the mathematical theorem, just know that with two vectors 120 degrees apart from each other, there actual distance is the Square Root of Three or ~1.73. Therefore, When measuring P - P 120V phases, the voltage will be 208V. So, L1 - L2 = 208V, L2 - L3 = 208V and L3 - L1 = 208V.
Clarification on 208V being 'Commercial' - It's not
Some utilities use a Three Phase Wye, 120/208V power transformer to feed a condominium complex. They do this because it is cheaper to set a single transformer for both single phase and three phase then to have multiple three-phase and single phase transformers. In this case, some condominiums and small businesses may actually have Single Phase 120/208V service drop and not 120/240V. Again, the reason is that the power company chose to feed the Single Phase service off of a Three-Phase 120/208V transformer.
I hope this helps and was not too technical.
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hacer
Active Member
I think it's worth pointing out that with single phase the available power "ripples" at twice the line frequency with peaks that are twice as large as the average available and troughs of zero power. This rippling reduces efficiency. With three phase power it is possible to "smooth out" the ripples so that the peak power is the same as the average power and this is more efficient. For a large electrical user, the increased efficiency of three phase is more valuable than the additional costs to have the service. For a residential user three phase is not very practical because almost nothing made for or used in a household can use three-phase power (e.g. any home-capacity sized air conditioner will be built to operate from single phase, while a factory-capacity sized air conditioner is usually built to operate from three-phase). This is why three-phase power is often called "commercial" because as a practical mater nearly all utility customers with three phase service are in fact commercial enterprises.
whitecotton
Member
hacer
Active Member
I'm not sure what part you're objecting to, but the rippling of single-phase AC power is illustrated here Wolfram Demonstrations Project and can also be found in nearly any text book on electric circuits.
An analysis showing that 3-phase power does not have this rippling is given here Three-phase - Wikipedia, the free encyclopedia in the section titled "Constant Power Transfer". Similar material can be found in many text books as well.
